1 //===-LTOCodeGenerator.h - LLVM Link Time Optimizer -----------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file declares the LTOCodeGenerator class. 11 // 12 // LTO compilation consists of three phases: Pre-IPO, IPO and Post-IPO. 13 // 14 // The Pre-IPO phase compiles source code into bitcode file. The resulting 15 // bitcode files, along with object files and libraries, will be fed to the 16 // linker to through the IPO and Post-IPO phases. By using obj-file extension, 17 // the resulting bitcode file disguises itself as an object file, and therefore 18 // obviates the need of writing a special set of the make-rules only for LTO 19 // compilation. 20 // 21 // The IPO phase perform inter-procedural analyses and optimizations, and 22 // the Post-IPO consists two sub-phases: intra-procedural scalar optimizations 23 // (SOPT), and intra-procedural target-dependent code generator (CG). 24 // 25 // As of this writing, we don't separate IPO and the Post-IPO SOPT. They 26 // are intermingled together, and are driven by a single pass manager (see 27 // PassManagerBuilder::populateLTOPassManager()). 28 // 29 // The "LTOCodeGenerator" is the driver for the IPO and Post-IPO stages. 30 // The "CodeGenerator" here is bit confusing. Don't confuse the "CodeGenerator" 31 // with the machine specific code generator. 32 // 33 //===----------------------------------------------------------------------===// 34 35 #ifndef LTO_CODE_GENERATOR_H 36 #define LTO_CODE_GENERATOR_H 37 38 #include "llvm-c/lto.h" 39 #include "llvm/ADT/ArrayRef.h" 40 #include "llvm/ADT/SmallPtrSet.h" 41 #include "llvm/ADT/StringMap.h" 42 #include "llvm/Linker/Linker.h" 43 #include "llvm/Target/TargetOptions.h" 44 #include <string> 45 #include <vector> 46 47 namespace llvm { 48 class LLVMContext; 49 class DiagnosticInfo; 50 class GlobalValue; 51 class Mangler; 52 class MemoryBuffer; 53 class TargetLibraryInfo; 54 class TargetMachine; 55 class raw_ostream; 56 57 //===----------------------------------------------------------------------===// 58 /// C++ class which implements the opaque lto_code_gen_t type. 59 /// 60 struct LTOCodeGenerator { 61 static const char *getVersionString(); 62 63 LTOCodeGenerator(); 64 ~LTOCodeGenerator(); 65 66 // Merge given module, return true on success. 67 bool addModule(struct LTOModule*, std::string &errMsg); 68 69 void setTargetOptions(TargetOptions options); 70 void setDebugInfo(lto_debug_model); 71 void setCodePICModel(lto_codegen_model); 72 setCpuLTOCodeGenerator73 void setCpu(const char *mCpu) { MCpu = mCpu; } setAttrLTOCodeGenerator74 void setAttr(const char *mAttr) { MAttr = mAttr; } 75 addMustPreserveSymbolLTOCodeGenerator76 void addMustPreserveSymbol(const char *sym) { MustPreserveSymbols[sym] = 1; } 77 78 // To pass options to the driver and optimization passes. These options are 79 // not necessarily for debugging purpose (The function name is misleading). 80 // This function should be called before LTOCodeGenerator::compilexxx(), 81 // and LTOCodeGenerator::writeMergedModules(). 82 void setCodeGenDebugOptions(const char *opts); 83 84 // Parse the options set in setCodeGenDebugOptions. Like 85 // setCodeGenDebugOptions, this must be called before 86 // LTOCodeGenerator::compilexxx() and LTOCodeGenerator::writeMergedModules() 87 void parseCodeGenDebugOptions(); 88 89 // Write the merged module to the file specified by the given path. 90 // Return true on success. 91 bool writeMergedModules(const char *path, std::string &errMsg); 92 93 // Compile the merged module into a *single* object file; the path to object 94 // file is returned to the caller via argument "name". Return true on 95 // success. 96 // 97 // NOTE that it is up to the linker to remove the intermediate object file. 98 // Do not try to remove the object file in LTOCodeGenerator's destructor 99 // as we don't who (LTOCodeGenerator or the obj file) will last longer. 100 bool compile_to_file(const char **name, 101 bool disableOpt, 102 bool disableInline, 103 bool disableGVNLoadPRE, 104 std::string &errMsg); 105 106 // As with compile_to_file(), this function compiles the merged module into 107 // single object file. Instead of returning the object-file-path to the caller 108 // (linker), it brings the object to a buffer, and return the buffer to the 109 // caller. This function should delete intermediate object file once its content 110 // is brought to memory. Return NULL if the compilation was not successful. 111 const void *compile(size_t *length, 112 bool disableOpt, 113 bool disableInline, 114 bool disableGVNLoadPRE, 115 std::string &errMsg); 116 117 void setDiagnosticHandler(lto_diagnostic_handler_t, void *); 118 119 private: 120 void initializeLTOPasses(); 121 122 bool generateObjectFile(raw_ostream &out, bool disableOpt, bool disableInline, 123 bool disableGVNLoadPRE, std::string &errMsg); 124 void applyScopeRestrictions(); 125 void applyRestriction(GlobalValue &GV, const ArrayRef<StringRef> &Libcalls, 126 std::vector<const char *> &MustPreserveList, 127 SmallPtrSet<GlobalValue *, 8> &AsmUsed, 128 Mangler &Mangler); 129 bool determineTarget(std::string &errMsg); 130 131 static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context); 132 133 void DiagnosticHandler2(const DiagnosticInfo &DI); 134 135 typedef StringMap<uint8_t> StringSet; 136 137 LLVMContext &Context; 138 Linker IRLinker; 139 TargetMachine *TargetMach; 140 bool EmitDwarfDebugInfo; 141 bool ScopeRestrictionsDone; 142 lto_codegen_model CodeModel; 143 StringSet MustPreserveSymbols; 144 StringSet AsmUndefinedRefs; 145 MemoryBuffer *NativeObjectFile; 146 std::vector<char *> CodegenOptions; 147 std::string MCpu; 148 std::string MAttr; 149 std::string NativeObjectPath; 150 TargetOptions Options; 151 lto_diagnostic_handler_t DiagHandler; 152 void *DiagContext; 153 }; 154 } 155 #endif // LTO_CODE_GENERATOR_H 156